December 2017 Newsletter:

Approaches to Environmental Assessments

As environmental consultants, we are tasked with formulating an environmental assessment plan that will answer as many questions as possible, as thoroughly as possible, for the least amount of cost and effort. Size of the land (acreage), buildings and improvements, history, location and topography all have impacts on the way an evaluation is approached.

At a professional society meeting recently the NCDOT supervisor for environmental assessment and remediation gave an illustrated discussion of how the NCDOT approaches environmental evaluation. The evaluation begins with a desk-top overview of a parcel or area. Things such as aerial photos, land-use records and other available documentation are reviewed to see if there are potential past uses of the property that could cause concerns. Things such as chemical use and storage, housekeeping practices, and spill response are examined. If there is sufficient concern based on the results of the desktop study, a second phase of investigation is initiated. In most cases, a surface geophysical study is performed to investigate for Underground Storage Tanks and possibly other conduits or buried storage containers. These investigations primarily focus on metal detection. The DOT has a well-structured evaluation of geophysical surveys to determine the amount of certainty of the findings.

The results of the geophysical survey are incorporated with other information to determine a plan for soil and groundwater sampling. The objective is to measure levels and extents of any soil or groundwater impacts from chemicals. The complexity of the site and the requirements of the project, such as depth of required excavation, emplacement of conduits, piping and other infrastructure, either now or in the future, can make the environmental aspects of a large construction project significant and complex.

ASTM is a well-known source of standards for performing environmental assessment. The ASTM standard E1527 is widely used as the guideline for Phase I investigations. This standard relies on desktop and publicly available records as a preliminary evaluation of a property. The objective is to identify the presence or absence of Recognized Environmental Conditions (RECs). The standard is well documented and so there should not be significant variations between the scope of work of different consultants.

ASTM also has a standard for Phase II environmental assessments. This standard is less specific in terms of establishing a thorough site evaluation, and therefore there is more reliance on the judgements of consultants and other parties involved. It does provide information on who is considered a qualified professional for performing a Phase II assessment. It also outlines significant required aspects of a Phase II that should be addressed, and includes an outline of a comprehensive recommended table of contents. The Phase II standard is E1903-11 and can be purchased at www.ASTM.org.